1. Field of the Invention
The present invention relates to a packaged air conditioner, and more particularly, to an indoor unit of a packaged air conditioner enabling to reduce both power consumption and noise by decreasing a system resistance using a cross-flow fan as a ventilator sucking in an indoor air compulsorily and blowing it to an evaporator.
2. Discussion of the Related Art
In general, an air conditioner is one of air controlling devices for cooling and ventilation/purification of an air for the purpose of pleasant air conditioning of an indoor environment. Such air conditioners are divided into a built-in-one-body type in which parts constructing a cooling cycle are established on one unit and a separate type in which the parts are established on separate units. Instead, the air conditioners may be divided in accordance with the product features into a wall suspension type of which indoor unit is hung on a wall, a floor mounting type of which indoor unit is established on a floor, and a ceiling suspension type of which indoor unit is suspended at a ceiling or hidden away inside the ceiling.
A packaged air conditioner is a separate floor mounting type, which is mounted on a floor to cool down a relatively-large indoor space, as a widely-adopted air conditioner. Such a packaged air conditioner cools an indoor space in a following manner that: a refrigerant gas having been compressed by a compressor is liquefied by exchanging heat with an outdoor air in a condenser; and the refrigerant liquid having passed through an expansion valve experiences a heat exchange with an outdoor air in an evaporator. Thus, the indoor space is cooled down using an evaporation heat of the heat-exchanging refrigerant.
The packaged air conditioner is generally constructed with an outdoor unit having built-in compressor and condenser to compress and liquefy a refrigerant and an indoor unit having built-in evaporator and the like to evaporate the refrigerant.
A structure of the packaged air conditioner is explained schematically as follows by referring to the attached drawings.
FIG. 1A and FIG. 1B illustrate front and objective views of a general packaged air conditioner.
Referring to FIG. 1A and FIG. 1B, an indoor unit of a packaged air conditioner includes a case 1 having an inlet grill 2 at a lower front part and an outlet grill 3 at an upper front, an evaporator 4 established on the slant at an inner upper part of the case 1 to cool an indoor air, and a blower 10 installed under the evaporator 4 to compulsorily inhale to blow the indoor air to the evaporator 4.
The blower 10 is placed at a rear of the inlet grill 2 for a smooth inhaling of the indoor air. In this case, the blower 10 uses a centrifugal fan in general such as a sirocco fan. The sirocco fan 10 inhales an air in an axis direction and blows the inlet air in a radial direction, for which a rotary axis is installed in a width direction of the case 1. The sirocco fan 10 includes an impeller 11 comprising a plurality of blades of which ends are bent in a rotary direction, a scroll housing 12 surrounding a circumference of the impeller 11 so as to provide a flow path of a blown air, and a motor 15 coupled with the rotary axis of the impeller 11. In this case, an outlet of the scroll housing 12 is open toward the evaporator 4 upward.
In the above-constructed sirocco fan, the indoor air inhaled into an eye of the impeller 11 is blown in the radial direction of the impeller 11 by a rotary movement of the blades and then guided into the evaporator 4 through an outlet of the scroll housing 12.
A drain pan 5 collecting a condensate of water generated massively from a surface of the evaporator 4 during a cooling of the air is placed below the evaporator 4. And, a condensate outlet 5a connected to an additional drain pipe (not shown in the drawing) is formed at a lower part of the drain pan 5.
The above-constructed packaged air conditioner is operated provided that a temperature of an indoor air is below a set temperature or a user carries out a compulsory operation of applying a power to the sirocco fan 10. The operating sirocco fan inhales the indoor air through the inlet grill 2 in an axis direction of the sirocco fan 10 so as to blow the inhaled air to the evaporator through the outlet of the scroll housing 12. In this case, the indoor air is cooled down by endothermic effect of the refrigerant as passing through the evaporator 4 and then blown into the indoor through the outlet grill 3, thereby cooling down the indoor space.
Unfortunately, the sirocco fan used as a blower in the above packaged air conditioner brings about the following problems/disadvantages.
First, the sirocco fan 10 fails to provide massive airflow having a constant pressure due to the above-explained fluid path structure despite providing such advantages as low RPM(revolutions per minute), small volume and the like in comparison with other types.
Second, the above-explained flow path of the sirocco fan is improper for an indoor unit of a packaged air conditioner, thereby increasing a system resistance. Namely, the sirocco fan 10 has the flow path through which an air is inhaled in the axis direction of the impeller 11 and the air is blown in the radial direction. In order to blow the air toward the evaporator 4 over the sirocco fan 10 of the indoor unit of the packaged air conditioner, the scrolling housing 12 should guide the blown. Such a process inevitably generates a measurable resistance of the flow path of air. As a result, the resistance by the flow path brings about a considerable noise during operation as well as increases power consumption.
Such a problem is more serious in a packaged air conditioner using a 3-way inlet type. Namely, an indoor air inhaled through inlet grills established at a front and both edges between lateral sides of a case should experience considerable resistances of the path flow so as to be inhaled in an axis direction of a sirocco fan. Therefore, power consumption should increase in comparison with the same airflow as well as causing a considerable noise.
Third, there is a limit to reducing a total width of a system in the indoor unit of the packaged air conditioner according to the related art. Namely, the rotary axis of the impeller 11 is installed along a width direction of the case 1 due to a structural characteristic of the flow path as well as the motor 15 should be placed at one end of the rotary axis. Therefore, a width of the indoor unit of the packaged air conditioner according to the related art should depend on a length of the sirocco fan and a size of the motor 15. Unfortunately, there should be a limit to the length of the impeller of the sirocco fan to attain a predetermined airflow, which fails to make a thin case.